The present invention relates to detector units of detector systems, such as fire alarm systems, to the detector system as a whole, to a remote communication device, and to associated methods of operation.
Modern fire alarm systems include a number of fire detector units and ancillary units which are connected to a common wired network together with a central control unit to which the network and all of the detectors and other ancillaries are connected. The central control unit in this specification is control and indicating equipment which instructs each fire detector unit and ancillary unit to perform various tasks during commissioning of the system, maintenance or diagnostic testing, and which controls the alarm system and the various units on the system. The fire detector and ancillary units are normally connected to the central control unit on one or more circuits or loops, with each end of the circuit terminating at the central control unit. Thus, if the circuit is broken at any one point, power and control signals can still reach every detector or ancillary unit because each end of the circuit is connected to the central control unit. Alternatively, the detector and ancillary units can be connected to the central control unit radially, or in other ways, such as a spur.
There are a number of operations which the central control unit instructs the detector units and ancillary units to perform. These can include putting units in different operating modes, activation of self test routines, programming the unit with a unique device identification and ancillary functions such as switch control.
It may be necessary for manual interaction with the units so as to facilitate or confirm operation of each unit's functions. For example, automated addressing algorithms from the central control unit can be used to uniquely identify and communicate with units on a wired network, but they may not be able to identify the physical location of each unit. During the commissioning process, in which the system is initially set up for correct functioning, an operator is required to be in a position near to the individual units. During the commissioning process, as well as testing the operation of the individual units, the nearby operator will need to identify the location of each unit. This normally requires a second operator at the central control unit who will send commands through the wired network to the unit near to the nearby operator such that a visible LED on the casing of the unit is caused to flash. The nearby operator must then communicate the location of the unit back to the operator at the central control unit perhaps by telephone or radio. The operator at the central control unit can then enter or confirm a pre-programmed location of the unit, for example “Conference Room 2” and send this through the wired network to the unit concerned where the location is stored in memory.
An alternative method exists in which a single operator carries a portable tool which he carries around the building so that, when he reaches a unit, he removes it from its mounting and connects it to the portable tool and uses the tool to write the location of the unit into the unit's memory. He then replaces the unit into its housing. This system has a number of problems in that units tend to be located in places which are difficult to access, such as high up on ceilings and in roof voids which require the use of specialist removal, climbing or lifting equipment to obtain access. This adds to the resources which are required to commission a system, and are time consuming, thereby incurring high commissioning, maintenance and diagnostic costs.
It has been proposed that remote devices are used to communicate with the units based on radio frequency (RF) signals, but there are a number of problems associated with this. Firstly, RF signals propagate over long distances and lack directionality. Thus, any signal which is emitted from the remote device is likely to be received by several units within the building. Also, many other devices operate using RF signals, meaning that there is a possibility of interference between the systems. It would be very undesirable for a unit to receive a signal from another system which causes it to enter a test mode whereby, if it were to detect the presence of a fire, it would not set off an alarm signal. It would also be undesirable if the remote device were to succeed in programming more than one unit at a time, when it is only intended to be used to program one of them. RF systems also tend to be very expensive.
Reference is made to ‘detector systems’. In the specification, this term includes systems, such as fire alarm systems, emergency alarm systems, intruder alarm systems and the like. The systems include a number of active units which are networked together, often on a circuit. The term ‘active units’ includes detector units for detecting whatever it is that the system is designed to detect, as well as ancillary units having different functions, such as sounders for generating an audible alarm, flashing beacons which provide a visual alarm, isolator units which can be used to isolate parts of a detector circuit, alarm activation buttons or switches, and the like. Where it is a fire detector system, the detector unit might be a smoke detector, heat detector, flame detector or the like. Where the detector system is an emergency detector system, it will include suitable detectors for detecting an emergency, such as the presence of toxic gases, the presence of radioactivity, or some other suitable indicator of an emergency. In the case of an intrusion detector system, the detector units might be movement detectors, heat detectors, pressure sensors, and the like.